PROJECT SUMMARY/ABSTRACT The role of the Biostatistics Core is to support investigators of the SPORE in Prostate Cancer in their research efforts, including laboratory experiments and the design and analysis of clinical trials. For preclinical studies, core members will assist in the formulation of the experimental design and in the analysis and interpretation of the data at the conclusion of the studies. A core member will conduct a protocol review with the principal investigator during the clinical trial design phase. Based on this review, we will provide a statistical section for the protocol, outlining major scientific objectives, population to be studied, primary and secondary endpoints, experimental design, a randomization procedure if necessary, analysis plans, and a targeted sample size justified in probabilistic terms. At the conclusion of the trial, data analyses will be performed to assess outcomes of the primary and secondary endpoints stated in the protocol. If current statistical methodology does not adequately address a research question in this SPORE, alternative methodologies will be explored. Examples of statistical research spawned from collaborations with clinical and laboratory researchers at Memorial Sloan Kettering Cancer Center include the following areas: clinical and preclinical trial design, and data analysis. The specific aims of the Biostatistics Core are to: Aim 1. Contribute to the design and analysis of laboratory-based prostate cancer research; Aim 2. Contribute to the design and analysis of clinical studies in prostate cancer; Aim 3. Develop statistical methodology that will assist in the advancement of prostate cancer research.